In recent years considerable time and effort has been devoted to improvements in buoyancy apparatus for scuba divers for increasing safety and convenience when ascending and descending in the water, so better buoyancy control is possible. A number of Letters Patents of the United States have been granted on such improvements. U.S. Pat. No. 3,964,266 to Bartlett discloses a buoyancy compensating back pack assembly, using a container of pressurized air having a depth actuated control valve with two outlets. One outlet is connected to a mouthpiece for providing air to the diver. The second outlet is also connected to a mouthpiece and to a confined air space that provides buoyancy in the water; the air exhaled by the diver may be passed by this second mouthpiece to the confined air space to provide increased buoyancy. This apparatus cannot automatically compensate for changes in the buoyancy of the diver's foam rubber wetsuit, and it has no failsafe features. Buckle, in U.S. Pat. No. 4,009,583, discloses a buoyancy control apparatus that includes a waterproof reservoir having a compressed air valve and a water valve. Compressed air or water is selectively introduced into the reservoir through the valves, with one fluid displacing the other, to increase or decrease the buoyancy. This apparatus cannot compensate automatically for wetsuit buoyancy changes, and it has no failsafe features. Another buoyancy compensation apparatus is U.S. Pat. No. 4,114,389, granted to Bohmrich et al, which employs a constant volume chamber that is controllably pressurized through the diver's scuba tank, with water being alternately admitted into the chamber by one of two valves. Again this apparatus cannot compensate automatically for changes in the wetsuit's buoyancy, and it does not contain any failsafe features. Buoyancy control apparatus is also disclosed in U.S. Pat. No. 3,747,140, granted to Roberts, which employs an air-filled vest with manually controllable air valve means for introducing compressed air from the scuba tank into the air vest when extra buoyancy is desired. This apparatus cannot automatically compensate for any buoyancy changes.
East's U.S. Pat. No. 3,820,348 discloses automatic buoyancy regulating apparatus, including flexible bladders that inflate (deflate) as their volume tends to decrease (increase) so as to maintain approximately constant bladder volume and buoyancy. A predetermined buoyancy is maintained by means of a stationary plate and a movable plate on opposite sides of each air bladder, with a tensioned cable surrounding these bladders and connected to valve means. When the surrounding water pressure increases (decreases), the moveable plates move toward (away from) the stationary plates, causing the cable's tension to decrease (increase). The cable then opens a valve causing air to enter (exit) the bladders, thus expanding (compressing) the bladders until the cable closes the valve. This cable's tension is also influenced by a pad of wetsuit material sandwiched between two plates, so that its tension monitors changes in the diver's wetsuit density and the wetsuit's corresponding buoyancy. Thus East's apparatus can compensate for changes in the wetsuit's buoyancy. However, this apparatus does not contain a convenient knob for fine tuning the apparatus to compensate for different wetsuits, nor does it contain any failsafe features to insure that the diver can manually control his buoyancy if necessary.
The present invention contains a convenient knob for fine tuning the apparatus to compensate for different wetsuits, it has failsafe features to insure that buoyancy can be manually controlled if necessary, and it can take the form of conventional buoyancy vests which are safer to use and more comfortable to wear than East's apparatus.